1. Field of the Invention
The invention relates to a novel hydrogen/oxygen fuel cell. More particularly, this invention relates to a hydrogen/oxygen fuel cell having a novel valving system for controlling the flow of gaseous fuel into the cell.
2. Prior Art
A fuel cell assembly for generating electrical energy by reacting gaseous reactants with a liquid electrolyte are well known in the art. For example, such cells are described in detail in German Pat. No. 2,129,134 and U.S. Pat. No. 3,935,028. In these known fuel cell assemblies, diaphragm valves are arranged in the working lines which are the feed lines for the gaseous reactants. In addition, a control line containing a pneumatic valve and a reducing valve are provided for feeding one of the gaseous reactants from the corresponding working line to an electrolyte regenerator. This control line also includes a magnetic valve which is positioned between the pneumatic valve and the reducing valve. The magnetic valve responds to the lower voltage limit of the fuel cell. The two diaphragm valves in each of the feed lines are connected to this magnetic valve, which provides control lines for the diaphragm valves.
When starting up hydrogen/oxygen fuel cell assemblies, because of the danger of oxidative damage to the hydrogen electrodes and catalysts, it is desirable to first feed the hydrogen to the fuel cell and then the gaseous oxidant. In known hydrogen/oxygen fuel cells, this is achieved by preceding the diaphragm valve for the oxidant in the respective control line by a choke. The choke causes the diaphragm valve for the oxidant to open later than the diaphragm valve for the gaseous fuel, whereby the desired purpose is achieved.
These known hydrogen/oxygen fuel cells suffer from a number of disadvantages that interfere with their effectiveness. For example, while theoretically a solution to the problem, control of the oxygen gas flow by means of a choke nozzle is difficult to realize in practice and in addition, proper operation cannot be assured with a certainty. This is because the volume of the control line from the choke nozzle to the oxygen diaphragm valve including the diaphragm space is relatively small, and, therefore, the opening pressure of the oxygen diaphragm valve is reached very quickly through the inflowing hydrogen control gas. In addition, if an appreciable difference in the opening instant of the hydrogen and the oxygen diaphragm valve is desired, then the diameter of the choke nozzle can only be about 0.03 to 0.1 mm, depending on the delay time desired. Such nozzles, however, not only are difficult to make in a reproducible manner, but they also require the use of a filtered gas because otherwise, they clog up easily. The known hydrogen/oxygen fuel cell has the further diadvantage that oxygen would flow into the battery even if the hydrogen diaphragm valve does not open, which could result in oxidative damage to the hydrogen electrodes and the catalyst.
It is therefore an object of the invention to provide a hydrogen/oxygen fuel cell with feed lines, diaphragm valves and control lines for the oxygen and hydrogen gases such that the hydrogen pressure prevailing in the cell is always higher than the oxygen pressure.
It is another object of this invention to provide a control for the inflow of hydrogen and oxygen gases so that oxidative damage to the hydrogen electrode and the catalyst will be prevented.
Other objects and advantages will be apparent to those of skill in the art from a reading of the specification and appended claims.